feat: 品牌替换 + 启动优化 + AGENTS.md 模板定制

- 品牌替换：OpenCode/opencode → AirCoding/aircoding（16+ 文件）
- Logo ASCII art：修复 left/right 行数不匹配导致的启动崩溃
- 启动诊断：添加 OPENCODE_PRINT_TIMING 计时探针
- dev 模式默认 --pure 跳过外部插件加载
- AGENTS.md 模板：追加 AirCoding 多 Agent 专项段落
- architect prompt + plugin：强化 AGENTS.md 产出验证

.opencode/command/issues.md

@@ -0,0 +1,23 @@
+---
+description: "find issue(s) on github"
+model: opencode/claude-haiku-4-5
+---
+
+Search through existing issues in anomalyco/opencode using the gh cli to find issues matching this query:
+
+$ARGUMENTS
+
+Consider:
+
+1. Similar titles or descriptions
+2. Same error messages or symptoms
+3. Related functionality or components
+4. Similar feature requests
+
+Please list any matching issues with:
+
+- Issue number and title
+- Brief explanation of why it matches the query
+- Link to the issue
+
+If no clear matches are found, say so.